Thermoplastic Polyolefin Blends Having Improved Low Temperature Impact Performance

ABSTRACT

A composition comprising (A) from 30 wt % to 70 wt % of a propylene component including at least one propylene based polymer having a propylene content of at least 70.0 wt %, based on the total weight of the propylene based polymer, and a melt flow rate from 1.0 g/10 min to 100.0 g/10 min (ASTM D-1238 at 230° C., 2.16 kg); (B) from 1 wt % to 20 wt % of an ethylene component including at least one ethylene based polymer having an ethylene content of at least 85.0 wt %, based on the total weight of the ethylene based polymer, and a melt index from 0.1 g/10 min to 50.0 g/10 min (ASTM D-1238 at 190° C., 2.16 kg); (C) from 1 wt % to 40 wt % of an olefin block copolymer; and at least one of (D) from 1 wt % to 40 wt % of a polyolefin elastomer and (E) from 1 wt % to 30 wt % of a filler.

FIELD

Embodiments relate to thermoplastic polyolefin blends that include apropylene component, an ethylene component, an olefin block copolymer,and at least one of a polyolefin elastomer and a filler.

INTRODUCTION

Thermoplastic polyolefin (TPO) formulations are widely used inautomotive applications, such as bumper fascia, instrument panels, doortrims, airbag covers, etc. Polymer blends are highly competitive for TPOapplications in terms of both cost and performance. Such blends include,for example, polypropylene impact copolymers (PP ICP), which provide lowtemperature impact performance. Use of ethylene based materials toreplace part of the polypropylene could provide a solution to bettermanage the balance of cost and physical properties of the blends.However, a barrier to such a solution is the incompatibility betweenpolyethylene and polypropylene which results in immiscible blends withpoor low temperature impact performance. Accordingly, a need exists forcompatibilized polyolefin blends that demonstrate improved impactresistance, especially at low temperatures, in such formulations wherepolypropylene is replaced with polyethylene.

SUMMARY

Embodiments may be realized by providing a composition comprising:

(A) from 30 wt % to 70 wt % of a propylene component including at leastone propylene based polymer having a propylene content of at least 70.0wt %, based on the total weight of the propylene based polymer, and amelt flow rate from 1.0 g/10 min to 100.0 g/10 min (ASTM D-1238 at 230°C., 2.16 kg);(B) from 1 wt % to 20 wt % of an ethylene component including at leastone ethylene based polymer having an ethylene content of at least 85.0wt %, based on the total weight of the ethylene based polymer, and amelt index from 0.1 g/10 min to 50.0 g/10 min (ASTM D-1238 at 190° C.,2.16 kg);(C) from 1 wt % to 40 wt % of an olefin block copolymer; and at leastone of (D) from 1 wt % to 40 wt % of a polyolefin elastomer and (E) from1 wt % to 30 wt % of a filler.

DETAILED DESCRIPTION Terms

The numerical ranges in this disclosure are approximate, and thus mayinclude values outside of the range unless otherwise indicated.Numerical ranges include all values from and including the lower and theupper values, in increments of one unit, provided that there is aseparation of at least two units between any lower value and any highervalue. As used with respect to a chemical compound, unless specificallyindicated otherwise, the singular includes all isomeric forms and viceversa.

All references to the Periodic Table of the Elements herein shall referto the Periodic Table of the Elements, published and copyrighted by CRCPress, Inc., 2003. Also, any references to a Group or Groups shall be tothe Group or Groups reflected in this Periodic Table of the Elementsusing the IUPAC system for numbering groups. Unless stated to thecontrary, implicit from the context, or customary in the art, all partsand percents are based on weight. For purposes of United States patentpractice, the contents of any patent, patent application, or publicationreferenced herein are hereby incorporated by reference in their entirety(or the equivalent US version thereof is so incorporated by reference)especially with respect to the disclosure of synthetic techniques,definitions (to the extent not inconsistent with any definitionsprovided herein) and general knowledge in the art.

“Composition” and like terms mean a mixture or blend of two or morecomponents. “Blend,” “polymer blend,” and like terms mean a blend of twoor more polymers. Such a blend may or may not be miscible. Such a blendmay or may not be phase separated. Such a blend may or may not containone or more domain configurations, as determined from transmissionelectron spectroscopy, light scattering, x-ray scattering, and any othermethod known in the art.

“Polymer” means a compound prepared by polymerizing monomers, whether ofthe same or a different type. The generic term polymer embraces the termhomopolymer, usually employed to refer to polymers prepared from onlyone type of monomer, and the term interpolymer and copolymer as definedbelow. It also encompasses all forms of interpolymers, e.g., random,block, homogeneous, heterogeneous, etc.

“Interpolymer” and “copolymer” mean a polymer prepared by thepolymerization of at least two different types of monomers. Thesegeneric terms include both classical copolymers, i.e., polymers preparedfrom two different types of monomers, and polymers prepared from morethan two different types of monomers, e.g., terpolymers, tetrapolymers,etc.

The terms “ethylene/α-olefin interpolymer” and “ethylene/a-olefinmulti-block interpolymer,” as used herein, refer to an interpolymer thatcomprises a polymerized ethylene monomer and at least one α-olefin.

The terms “ethylene/α-olefin copolymer” and “ethylene/α-olefinmulti-block copolymer,” as used herein, further refer to a copolymerthat comprises a polymerized ethylene monomer and an α-olefin as theonly two monomer types.

“Units derived from ethylene,” “ethylene content,” and like terms meanthe units of a polymer that formed from the polymerization of ethylenemonomers. “Units derived from α-olefin,” “alpha-olefin content,”“α-olefin content,” and like terms mean the units of a polymer thatformed from the polymerization of specific α-olefin monomers, inparticular at least one of a C₃₋₁₀ α-olefin. “Units derived frompropylene,” “propylene content,” and like terms mean the units of apolymer that formed from the polymerization of propylene monomers.

“Propylene based polymer,” and like terms mean a polymer that comprisesa majority weight percent polymerized propylene monomer, also referredto as units derived from propylene (based on the total amount ofpolymerizable monomers), and optionally comprises at least onepolymerized comonomer different from propylene (such as at least oneselected from a C₂ and C₄₋₁₀ α olefin) so as to form a propylene-basedinterpolymer. For example, when the propylene-based polymer is acopolymer, the propylene content is greater than 50 wt %, based on thetotal weight of the copolymer.

“Ethylene based polymer” and like terms mean a polymer that comprises amajority weight percent polymerized ethylene monomer, also referred toas units derived from ethylene (based on the total weight ofpolymerizable monomers), and optionally may comprise at least onepolymerized comonomer different from ethylene (such as at least oneselected from a C₃₋₁₀ α olefin) so as to form an ethylene-basedinterpolymer. For example, when the ethylene-based polymer is acopolymer, the amount of ethylene is greater than 85 wt %, based on thetotal weight to the copolymer.

The term “polyethylene” includes homopolymers of ethylene and copolymersof ethylene and one or more C₃₋₈ α-olefins in which ethylene comprisesat least 50 mole percent. The term “polypropylene” includes homopolymersof propylene such as isotactic polypropylene, syndiotacticpolypropylene, and copolymers of propylene and one or more C_(2,4-8)α-olefins in which propylene comprises at least 50 mole percent.Preferably, a plurality of the polymerized monomer units of at least oneblock or segment in the polymer (a crystalline block) comprisepropylene, preferably at least 90 mole percent, more preferably at least93 mole percent, and most preferably at least 95 mole percent. A polymermade primarily from a different α-olefin, such as 4-methyl-1-pentenewould be named similarly.

The term “crystalline” refers to a polymer or polymer block thatpossesses a first order transition or crystalline melting point (Tm) asdetermined by differential scanning calorimetry (DSC) or equivalenttechnique. The term may be used interchangeably with the term“semicrystalline”.

The term “crystallizable” refers to a monomer that can polymerize suchthat the resulting polymer is crystalline. Crystalline ethylene polymerstypically have, but are not limited to, densities of 0.89 g/cc to 0.97g/cc and melting points of 75° C. to 140° C. Crystalline propylenepolymers may have, but are not limited to, densities of 0.88 g/cc to0.91 g/cc and melting points of 100° C. to 170° C.

The term “amorphous” refers to a polymer lacking a crystalline meltingpoint as determined by differential scanning calorimetry (DSC) orequivalent technique.

The term “isotactic” is defined as polymer repeat units having at least70 percent isotactic pentads as determined by ¹³C-NMR analysis. “Highlyisotactic” is defined as polymers having at least 90 percent isotacticpentads.

Propylene Component

The composition includes from 30 wt % to 70 wt % (e.g., from 35 wt % to70 wt %, from 40 wt % to 70 wt %, from 45 wt % to 65 wt %, etc.) of apropylene component. The propylene component includes one or morepropylene based polymers having a propylene content of at least 70.0 wt%, based on the total weight of the propylene based polymer. The one ormore propylene based polymer has a melt flow rate from 0.1 g/10 min to500.0 g/10 min, according to ASTM D-1238 or ISO 1133 at 230° C., 2.16 kg(e.g., from 1 g/10 min to 100.0 g/10 min, from 5 g/10 min to 75 g/10min, from 10 g/10 min to 50 g/10 min, etc.). The propylene based polymermay have a density, in accordance with ASTM D792 or ISO 1183, from 0.850g/cm³ to 0.950 g/cm³ (e.g., from 0.860 g/cc to 0.940 g/cc, from 0.875g/cc to 0.925 g/cc, from 0.880 g/cc to 0.910 g/cc, etc.). The propylenebased polymer may consist of heterogeneous polypropylene or homogeneouspolypropylene.

Each of the one of more propylene based polymers may be a propylenehomopolymer, propylene based interpolymers, a random copolymerpolypropylene (RCPP), an impact copolymer polypropylene (e.g.,homopolymer propylene modified with at least one elastomeric impactmodifier) (ICPP), a high impact polypropylene (HIPP), a high meltstrength polypropylene (HMS-PP), an isotactic polypropylene (iPP), asyndiotactic polypropylene (sPP), or a combination thereof In exemplaryembodiments, the one or more propylene based polymers may be in theisotactic form of homopolymer polypropylene, although other forms ofpolypropylene may be used (e.g., syndiotactic or atactic). In exemplaryembodiments, the one or more propylene based polymers may be apolypropylene homopolymer or an impact copolymer polypropylene.

The one or more propylene-based polymers are formed without the use of achain shuttling agent, as discussed below with respect to the blockcomposites. Exemplary comonomers for polymerizing with propylene includeethylene, 1-butene, 1 pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene,1-decease, 1-unidecene, 1 dodecene, as well as 4-methyl-1-pentene,4-methyl-1-hexene, 5-methyl-1-hexene, vinylcyclohexane, and styrene.Exemplary comonomers include ethylene, 1-butene, 1-hexene, and 1-octene.Exemplary propylene based interpolymers include propylene/ethylene,propylene/1-butene, propylene/1-hexene, propylene/4-methyl-1-pentene,propylene/1-octene, propylene/ethylene/1-butene, propylene/ethylene/ENB,propylene/ethylene/1-hexene, propylene/ethylene/1-octene,propylene/styrene, and propylene/ethylene/styrene. Optionally, thepropylene-based polymer include a monomer having at least two doublebonds such as dienes or trienes. Other unsaturated comonomers include,e.g., 1,3-pentadiene, norbornadiene, and dicyclopentadiene; C8-40 vinylaromatic compounds including styrene, o-, m-, and p-methylstyrene,divinylbenzene, vinylbiphenyl, vinylnapthalene; and halogen-substitutedC8-40 vinyl aromatic compounds such as chlorostyrene and fluorostyrene.

Exemplary propylene-based polymers are formed by means within the skillin the art, for example, using single site catalysts (metallocene orconstrained geometry) or Ziegler natta catalysts.

An exemplary discussion of various polypropylene polymers is containedin Modern Plastics Encyclopedia/89, mid October 1988 Issue, Volume 65,Number 11, pp. 86-92, the entire disclosure of which is incorporatedherein by reference. Examples of such propylene based polymers includeVERSIFY™ (available from The Dow Chemical Company), Vistamaxx™(available from Exxon Mobil), INSPIRE™ (available from Braskem), andPro-Fax (available from LyondellBasell).

In exemplary embodiments, the propylene-based polymer may be apropylene-alpha-olefin copolymer, which is characterized as havingsubstantially isotactic propylene sequences. “Substantially isotacticpropylene sequences” means that the sequences have an isotactic triad(mm) measured by ¹³C NMR of greater than 0.85; in the alternative,greater than 0.90; in another alternative, greater than 0.92; and inanother alternative, greater than 0.93.

Similarly as discussed with respect to the ethylene-based polymers, thepropylene-based polymers may contain LCB. For example, thepropylene-based polymer may contain an average of at least 0.001, anaverage of at least 0.005 and/or an average of at least 0.01, long chainbranches/1000 total carbons. The term long chain branch, as used herein,refers to a chain length of at least one (1) carbon more than a shortchain branch, and short chain branch, as used herein with regard topropylene/alpha-olefin copolymers, refers to a chain length of two (2)carbons less than the number of carbons in the comonomer. For example, apropylene/1-octene interpolymer has backbones with long chain branchesof at least seven (7) carbons in length, but these backbones also haveshort chain branches of only six (6) carbons in length.

Further parameters of the propylene-based polymers (e.g., molecularweight, molecular weight distribution, melting temperature, etc.) willbe known by those of ordinary skill in the art based on the presentdisclosures and can be determined by known methods in the polymer art.

Ethylene Component

The composition includes from 1 wt % to 20 wt % (e.g., 5 wt % to 20 wt%, 10 wt % to 20 wt %, 10 wt % to 15 wt % etc.) of an ethylenecomponent. The ethylene component includes one or more ethylene basedpolymers having an ethylene content of at least 85.0 wt %, based on thetotal weight of the ethylene based polymer. The one or more ethylenebased polymers have a melt index from 0.1 g/10 min to 100.0 g/10 min(e.g., from 0.3 g/10 min to 80.0 g/10 min, 0.3 g/10 min to 50.0 g/10min, 0.3 g/10 min to 30.0 g/10 min, 0.3 g/10 min to 20.0 g/10 min, 0.5g/10 min to 10.0 g/10 min, etc.), according to ASTM D-1238 or ISO 1133at 190° C., 2.16 kg. The ethylene based polymers have a density from0.900 g/cm³ to 0.980 g/cm³ (e.g., 0.925 g/cm³ to 0.975 g/cm³, 0.935g/cm³ to 0.970 g/cm³, 0.950 g/cm³ to 0.970 g/cm³, etc.) in accordancewith ASTM D792 or ISO 1183.

The ethylene component may include high density polyethylene (HDPE),medium density polyethylene (MDPE), linear low density polyethylene(LLDPE), or combinations thereof Exemplary other ethylene based polymersinclude ultralow density polyethylene (ULDPE), low density polyethylene(LDPE), high melt strength high density polyethylene (HMS-HDPE),ultrahigh density polyethylene (UHDPE), and combinations thereof. Inexemplary embodiments, the ethylene component includes at least 50 wt %,60 wt %, 70 wt %, 80 wt %, 90 wt %, 95 wt %, 99 wt %, etc., and/orincludes 100 wt % of HDPE type ethylene based polymers, based on thetotal amount of one or more ethylene based polymers in the ethylenecomponent.

The number average molecular weight (Mw) of the ethylene based polymersin the ethylene component may be at least 5,000, at least 10,000, atleast 15,000, at least 20,000, at least 25,000, and/or at least 30,000grams per mole (g/mol). The molecular weight distribution orpolydispersity or Mw/Mn of these polymers may be between 1 and 8. Weightaverage molecular weight (Mw) and number average molecular weight (Mn)are well known in the polymer art and can be determined by know methods.Further parameters of the ethylene-based polymers (e.g., meltingtemperature, etc.) will be known by those of ordinary skill in the artbased on the present disclosures and can be determined by known methodsin the polymer art.

Exemplary ethylene based polymers may include an ethylene/alpha-olefininterpolymer. The ethylene-based polymers are formed without the use ofa chain shuttling agent, as discussed below with respect to thecrystalline block composite. Such interpolymers include polymerspolymerized from at least two different monomers. They include, e.g.,copolymers, terpolymers and tetrapolymers. Exemplary, interpolymers areprepared by polymerizing ethylene with at least one comonomer, such asan alpha-olefin (α-olefin) of 3 to 20 carbon atoms (C₃-C₂₀), 4 to 20carbon atoms (C₄-C₂₀), 4 to 12 carbon atoms (C₄-C₁₂), 4 to 10 carbonatoms (C₄-C₁₀), and/or 4 to 8 carbon atoms (C₄-C₈). The alpha-olefinsinclude, but are not limited to, 1-butene, 1-pentene, 1-hexene,4-methyl- 1-pentene, 1-heptene, and 1-octene. In embodiments,alpha-olefins such as 1-butene, 1 pentene, 1-hexene, 4-methyl-1-pentene,1-heptene, and/or 1-octene are used. The alpha-olefin may be a C₄-C₈alpha-olefin.

Exemplary, interpolymers include ethylene/propylene (EP),ethylene/butene (EB) copolymers, ethylene/hexene (EH), ethylene/octene(EO) copolymers, ethylene/alpha-olefin/diene modified (EAODM)interpolymers such as ethylene/propylene/diene modified (EPDM)interpolymers, and ethylene/propylene/octene terpolymers.

In exemplary embodiments, the ethylene based polymers may be branchedand/or unbranched interpolymers. The presence or absence of branching inthe ethylene based interpolymers, and if branching is present, theamount of branching, can vary widely, and may depend on the desiredprocessing conditions and the desired polymer properties. Exemplarytypes of long chain branching (LCB) in the interpolymers include T-typebranching and H-type branching.

Olefin Block Copolymer

The composition includes from 1 wt % to 40 wt % of an olefin blockcopolymer. The term “olefin block copolymer” or “OBC” means (and isinterchangeable with) an ethylene/α-olefin interpolymer and includesethylene and one or more copolymerizable α-olefin comonomer inpolymerized form, characterized by multiple blocks or segments of two ormore polymerized monomer units differing in chemical or physicalproperties. When referring to amounts of “ethylene” or “comonomer” inthe interpolymer, it is understood that this means polymerized unitsthereof In some embodiments, the ethylene/α-olefin interpolymer is anethylene/α-olefin multi-block interpolymer. In further embodiments, theethylene/α-olefin interpolymer is an ethylene/α-olefin multi-blockcopolymer that can be represented by the following formula:

(AB)_(n),

where n is at least 1, preferably an integer greater than 1, such as 2,3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or higher, “A”represents a hard block or segment and “B” represents a soft block orsegment. Preferably, As and Bs are linked in a substantially linearfashion, as opposed to a substantially branched or substantiallystar-shaped fashion. In other embodiments, A blocks and B blocks arerandomly distributed along the polymer chain. In other words, the blockcopolymers usually do not have a structure as follows. AAA-AA-BBB-BB.

In certain embodiments, the block copolymers do not usually have a thirdtype of block, which comprises different comonomer(s). In yet otherembodiments, each of block A and block B has monomers or comonomerssubstantially randomly distributed within the block. In other words,neither block A nor block B comprises two or more sub-segments (orsub-blocks) of distinct composition, such as a tip segment, which has asubstantially different composition than the rest of the block.

Preferably, ethylene comprises the majority mole fraction of the wholeblock copolymer, i.e., ethylene comprises at least 50 mole percent ofthe whole polymer. More preferably ethylene comprises at least 60 molepercent, at least 70 mole percent, or at least 80 mole percent, with thesubstantial remainder of the whole polymer comprising at least one othercomonomer that is preferably an α-olefin having 3 or more carbon atoms.In some embodiments, the olefin block copolymer may comprise 50 mol % to90 mol % ethylene, preferably 60 mol % to 85 mol %, more preferably 70mol % to 85 mol %. For many ethylene/octene block copolymers, thepreferred composition comprises an ethylene content greater than 80 molepercent of the whole polymer and an octene content of from 10 to 15,preferably from 15 to 20 mole percent of the whole polymer.

The olefin block copolymer includes various amounts of “hard” and “soft”segments. “Hard” segments are blocks of polymerized units in whichethylene is present in an amount greater than 94 weight percent, orgreater than 98 weight percent based on the weight of the polymer, up to100 weight percent. In other words, the comonomer content (content ofmonomers other than ethylene) in the hard segments is less than 6 weightpercent, or less than 2 weight percent based on the weight of thepolymer, and can be as low as zero. In some embodiments, the hardsegments include all, or substantially all, units derived from ethylene.“Soft” segments are blocks of polymerized units in which the comonomercontent (content of monomers other than ethylene) is greater than 5weight percent, or greater than 8 weight percent, greater than 10 weightpercent, or greater than 15 weight percent based on the weight of thepolymer. In some embodiments, the comonomer content in the soft segmentscan be greater than 20 weight percent, greater than 25 weight percent,greater than 30 weight percent, greater than 35 weight percent, greaterthan 40 weight percent, greater than 45 weight percent, greater than 50weight percent, or greater than 60 weight percent and can be up to 100weight percent.

The soft segments can be present in an OBC from 1 weight percent to 99weight percent of the total weight of the OBC, or from 5 weight percentto 95 weight percent, from 10 weight percent to 90 weight percent, from15 weight percent to 85 weight percent, from 20 weight percent to 80weight percent, from 25 weight percent to 75 weight percent, from 30weight percent to 70 weight percent, from 35 weight percent to 65 weightpercent, from 40 weight percent to 60 weight percent, or from 45 weightpercent to 55 weight percent of the total weight of the OBC. Conversely,the hard segments can be present in similar ranges. The soft segmentweight percentage and the hard segment weight percentage can becalculated based on data obtained from DSC or NMR. Such methods andcalculations are disclosed in, for example, U.S. Pat. No. 7,608,668,entitled “Ethylene/α-Olefin Block Inter-polymers,” filed on Mar. 15,2006, in the name of Colin L. P. Shan, Lonnie Hazlitt, et. al. andassigned to Dow Global Technologies Inc., the disclosure of which isincorporated by reference herein in its entirety. In particular, hardand soft segment weight percentages and comonomer content may bedetermined as described in Column 57 to Column 63 of U.S. Pat. No.7,608,668.

The olefin block copolymer is a multi-block or segmented polymercomprising two or more chemically distinct regions or segments (referredto as “blocks”) preferably joined in a linear manner, that is, a polymercomprising chemically differentiated units which are joined end-to-endwith respect to polymerized ethylenic functionality, rather than inpendent or grafted fashion. In an embodiment, the blocks differ in theamount or type of incorporated comonomer, density, amount ofcrystallinity, crystallite size attributable to a polymer of suchcomposition, type or degree of tacticity (isotactic or syndiotactic),regio-regularity or regio-irregularity, amount of branching (includinglong chain branching or hyper-branching), homogeneity or any otherchemical or physical property. Compared to block interpolymers of theprior art, including interpolymers produced by sequential monomeraddition, fluxional catalysts, or anionic polymerization techniques, thepresent OBC is characterized by unique distributions of both polymerpolydispersity (PDI or Mw/Mn or MWD), block length distribution, and/orblock number distribution, due, in an embodiment, to the effect of theshuttling agent(s) in combination with multiple catalysts used in theirpreparation.

When produced in a continuous process, embodiments of the OBC maypossess a PDI ranging from 1.7 to 8; or from 1.7 to 3.5; or from 1.7 to2.5; and from 1.8 to 2.5; or from 1.8 to 2.1. When produced in a batchor semi-batch process, the OBC possesses PDI from 1.0 to 3.5, or from1.3 to 3, or from 1.4 to 2.5, or from 1.4 to 2.

Because the respective distinguishable segments or blocks formed fromtwo or more monomers are joined into single polymer chains, the polymercannot be completely fractionated using standard selective extractiontechniques. For example, polymers containing regions that are relativelycrystalline (high density segments) and regions that are relativelyamorphous (lower density segments) cannot be selectively extracted orfractionated using differing solvents. In an embodiment, the quantity ofextractable polymer using either a dialkyl ether or an alkane solvent isless than 10, or less than 7, or less than 5, or less than 2, percent ofthe total polymer weight.

In addition, the OBC disclosed herein possesses a PDI fitting aSchultz-Flory distribution rather than a Poisson distribution. Thepresent OBC is produced by the polymerization process described in U.S.Pat. No. 7,858,706 and U.S. Pat. No. 7,608,668 which results in aproduct having both a polydisperse block distribution as well as apolydisperse distribution of block sizes. This results in the formationof OBC product having distinguishable physical properties. Thetheoretical benefits of a polydisperse block distribution have beenpreviously modeled and discussed in Potemkin, Physical Review E (1998)57 (6), pp. 6902-6912, and Dobrynin, J. Chem. Phys. (1997) 107 (21), pp9234-9238. In an embodiment, the present olefin block copolymerpossesses a most probable distribution of block lengths. In anembodiment, the olefin block copolymer is defined as having:

(A) Mw/Mn from 1.7 to 3.5, at least one melting point, Tm, in degreesCelsius, and a density, d, in grams/cubic centimeter, where in thenumerical values of Tm and d correspond to the relationship:

-   -   Tm>−2002.9+4538.5(d)−2422.2(d)², and/or

(B) Mw/Mn from 1.7 to 3.5, and is characterized by a heat of fusion, ΔHin J/g, and a delta quantity, ΔT, in degrees Celsius defined as thetemperature difference between the tallest DSC peak and the tallestCrystallization Analysis Fractionation (“CRYSTAF”) peak, wherein thenumerical values of ΔT and ΔH have the following relationships:

-   -   ΔT>−0.1299ΔH+62.81 for ΔH greater than zero and up to 130 J/g,    -   ΔT≥48° C. for ΔH greater than 130 J/g,        wherein the CRYSTAF peak is determined using at least 5 percent        of the cumulative polymer, and if less than 5 percent of the        polymer has an identifiable CRYSTAF peak, then the CRYSTAF        temperature is 30° C.; and/or

(C) elastic recovery, Re, in percent at 300 percent strain and 1 cyclemeasured with a compression-molded film of the ethylene/α-olefininterpolymer, and has a density, d, in grams/cubic centimeter, whereinthe numerical values of Re and d satisfy the following relationship whenethylene/α-olefin interpolymer is substantially free of crosslinkedphase:

-   -   Re>1481-1629(d); and/or

(D) a molecular weight fraction which elutes between 40° C. and 130° C.when fractionated using TREF, characterized in that the fraction has amolar comonomer content of at least 5 percent higher than that of acomparable random ethylene interpolymer fraction eluting between thesame temperatures, wherein said comparable random ethylene interpolymerhas the same comonomer(s) and has a melt index, density and molarcomonomer content (based on the whole polymer) within 10 percent of thatof the ethylene/α-olefin interpolymer; and/or

(E) has a storage modulus at 25° C., G′ (25° C.), and a storage modulusat 100° C., G′(100° C.), wherein the ratio of G′ (25° C.) to G′ (100°C.) is in the range of 1:1 to 9:1.

The olefin block copolymer may also have:

(F) a molecular fraction which elutes between 40° C. and 130° C. whenfractionated using TREF, characterized in that the fraction has a blockindex of at least 0.5 and up to 1 and a molecular weight distribution,Mw/Mn, greater than 1.3; and/or

(G) average block index greater than zero and up to 1.0 and a molecularweight distribution, Mw/Mn greater than 1.3. It is understood that theolefin block copolymer may have one, some, all, or any combination ofproperties (A)-(G). Block Index can be determined as described in detailin U.S. Pat. No. 7,608,668 herein incorporated by reference for thatpurpose. Analytical methods for determining properties (A) through (G)are disclosed in, for example, U.S. Pat. No. 7,608,668, Col. 31, line 26through Col. 35, line 44, which is herein incorporated by reference forthat purpose.

The ethylene/α-olefin multi-block interpolymer, and further copolymer,may comprise any one of properties (A) through (G), or may comprises acombination of two or more of (A) through (G).

Another type of ethylene/α-olefin block interpolymers that may be usedare those referred to as “mesophase separated”. These mesodomains cantake the form of spheres, cylinders, lamellae, or other morphologiesknown for block copolymers. The narrowest dimension of a domain, such asperpendicular to the plane of lamellae, is generally greater than about40 nm in the mesophase separated block copolymers of the instantinvention. Examples of these interpolymers may be found in, for example,International Publication Nos. WO/2009/097560, WO/2009/097565,WO/2009/097525, WO/2009/097529, WO/2009/097532, and WO/2009/097535, allof which are herein incorporated by reference.

Suitable monomers for use in preparing the present OBC include ethyleneand one or more addition polymerizable monomers other than ethylene.Examples of suitable comonomers include straight-chain or branchedα-olefins of 3 to 30, preferably 3 to 20, carbon atoms, such aspropylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene,4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decease, 1-dodecene,1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosene; cyclo-olefinsof 3 to 30, preferably 3 to 20, carbon atoms, such as cyclopentene,cycloheptene, norbornene, 5-methyl-2-norbornene, tetracyclododecene, and2-methyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydro-naphthalene; di-and polyolefins, such as butadiene, isoprene, 4-methyl-1,3-pentadiene,1,3-pentadiene, 1,4-pentadiene, 1,5-hexadiene, 1,4-hexadiene,1,3-hexadiene, 1,3-octadiene, 1,4-octadiene, 1,5-octadiene,1,6-octadiene, 1,7-octadiene, ethylidenenorbornene, vinyl norbornene,dicyclopentadiene, 7-methyl-1,6-octadiene,4-ethylidene-8-methyl-1,7-nonadiene, and 5,9-dimethyl-1,4,8-decatriene;and 3-phenylpropene, 4-phenylpropene, 1,2-difluoroethylene,tetrafluoroethylene, and 3,3,3-trifluoro-1-propene. Preferred α-olefinsinclude, but are not limited to, C3-C20 α-olefins, and preferably C3-C10α-olefins. More preferred α-olefins include propylene, 1-butene,1-pentene, 1-hexene, 1-heptene and 1-octene, and more preferably includepropylene, 1-butene, 1-hexene and 1-octene.

The olefin block copolymers can be produced via a chain shuttlingprocess such as described in U.S. Pat. No. 7,858,706, which is hereinincorporated by reference. In particular, suitable chain shuttlingagents and related information are listed in Col. 16, line 39 throughCol. 19, line 44. Suitable catalysts are described in Col. 19, line 45through Col. 46, line 19 and suitable co-catalysts in Col. 46, line 20through Col. 51 line 28. The process is described throughout thedocument, but particularly in Col. Col 51, line 29 through Col. 54, line56. The process is also described, for example, in the following: U.S.Pat. No. 7,608,668; U.S. Pat. No. 7,893,166; and U.S. Pat. No.7,947,793.

In certain embodiments, the ethylene/α-olefin multi-block interpolymer,and further copolymer, has a density greater than 0.850 g/cc, furthergreater than 0.860 g/cc, and further greater than 0.865 g/cc. Thedensity may be, for example, from 0.850 g/cc to 0.950 g/cc, from 0.860g/cc to 0.925 g/cc, and from 0.860 to 0.900 g/cc. Density is measured bythe procedure of ASTM D-792.

In certain embodiments, the ethylene/α-olefin multi-block interpolymer,and further copolymer, has a melting point of greater than 90° C.,further greater than 100° C. The melting point is measured byDifferential Scanning calorimetry (DSC) method described in U.S.Publication 2006/0199930 (WO 2005/090427), incorporated herein byreference.

In certain embodiments, the ethylene/α-olefin multi-block interpolymer,and further copolymer, has a melt index (I2) greater than, or equal to,0.1 g/10 min, and further greater than, or equal to, 0.5 g/10 min, asdetermined using ASTM D-1238 or ISO 1133 (190° C., 2.16 kg load).

In certain embodiments, the ethylene/α-olefin multi-block interpolymer,and further copolymer, has a melt index (I2) less than, or equal to, 50g/10 min, further less than, or equal to, 20 g/10 min, and further lessthan, or equal to, 10 g/10 min, as determined using ASTM D-1238 or ISO1133(190° C., 2.16 kg load).

An ethylene/α-olefin multi-block interpolymer may comprise a combinationof two or more embodiments as described herein. An ethylene/α-olefinmulti-block copolymer may comprise a combination of two or moreembodiments as described herein.

Polyolefin Elastomer

The composition may include from 1 to 40 wt % of a polyolefin elastomer(e.g., from 5 wt % to 35 wt %, from 10 wt % to 30 wt %, etc.). Incertain embodiments of the present disclosure, the polyolefin elastomermay be used to toughen the propylene component of the composition.Suitable polyolefin elastomers may be any elastomer with sufficientpolypropylene compatibility and sufficiently low enough glass transitiontemperature to impart impact toughness to the propylene component. Inone embodiment, the polyolefin elastomer is a randomly copolymerizedethylene/alpha-olefin copolymer. In a further embodiment, the polyolefinelastomer is an ethylene/alpha-olefin interpolymer.

The ethylene/α-olefin random copolymers used as the toughening elastomerin the embodiments of the invention are preferably copolymers ofethylene with at least one C₃-C₂₀ α-olefin. Copolymers of ethylene and aC₃-C₂₀ α-olefin are especially preferred. Non-limiting examples of suchcopolymers are linear, homogeneously branched copolymers such as EXACT®from ExxonMobil and TAFMER® from Mitsui, and substantially linear,homogeneously branched copolymers such as AFFINITY® and ENGAGE®copolymers from the Dow Chemical Company. The copolymers may furthercomprise C₄-C₁₈ diolefin and/or alkenylbenzene. Suitable unsaturatedcomonomers useful for polymerizing with ethylene include, for example,ethylenically unsaturated monomers, conjugated or nonconjugated dienes,polyenes, alkenylbenzenes, etc. Examples of such comonomers includeC₃-C₂₀ α-olefins such as propylene, isobutylene, 1-butene, 1-hexene,1-pentene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene,and the like. 1-Butene and 1-octene are especially preferred. Othersuitable monomers include styrene, halo- or alkyl-substituted styrenes,vinylbenzocyclobutane, 1,4-hexadiene, 1,7-octadiene, and naphthenics(e.g., cyclopentene, cyclohexene and cyclooctene).

While ethylene/α-olefin copolymers are preferred polymers, otherethylene/olefin polymers may also be used. Olefins as used herein referto a family of unsaturated hydrocarbon-based compounds with at least onecarbon-carbon double bond. Depending on the selection of catalysts, anyolefin may be used in embodiments of the invention. Preferably, suitableolefins are C₃-C₂₀ aliphatic and aromatic compounds containing vinylicunsaturation, as well as cyclic compounds, such as cyclobutene,cyclopentene, dicyclopentadiene, and norbornene, including but notlimited to, norbornene substituted in the 5 and 6 position with C₁-C₂₀hydrocarbyl or cyclohydrocarbyl groups. Also included are mixtures ofsuch olefins as well as mixtures of such olefins with C₄-C₄₀ diolefincompounds.

Examples of olefin monomers include, but are not limited to propylene,isobutylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene,1-nonene, 1-decease, and 1-dodecene, 1-tetradecene, 1-hexadecene,1-octadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene,4-methyl-1-pentene, 4,6-dimethyl-1-heptene, 4-vinylcyclohexene,vinylcyclohexane, norbornadiene, ethylidene norbornene, cyclopentene,cyclohexene, dicyclopentadiene, cyclooctene, C₄-C₄₀ dienes, includingbut not limited to 1,3-butadiene, 1,3-pentadiene, 1,4-hexadiene,1,5-hexadiene, 1,7-octadiene, 1,9-decadiene, other C₄-C₄₀ α-olefins, andthe like. In certain embodiments, the α-olefin is propylene, 1-butene, 1-pentene, 1-hexene, 1-octene or a combination thereof Although anyhydrocarbon containing a vinyl group potentially may be used inembodiments of the invention, practical issues such as monomeravailability, cost, and the ability to conveniently remove unreactedmonomer from the resulting polymer may become more problematic as themolecular weight of the monomer becomes too high.

The polymerization processes described herein are well suited for theproduction of olefin polymers comprising monovinylidene aromaticmonomers including styrene, o-methyl styrene, p-methyl styrene,t-butylstyrene, and the like. In particular, interpolymers comprisingethylene and styrene can be prepared. Optionally, copolymers comprisingethylene, styrene and a C₃-C₂₀ alpha olefin, optionally comprising aC₄-C₂₀ diene, having improved properties can be prepared.

Suitable non-conjugated diene monomers can be a straight chain, branchedchain or cyclic hydrocarbon diene having from 6 to 15 carbon atoms.Examples of suitable non-conjugated dienes include, but are not limitedto, straight chain acyclic dienes, such as 1,4-hexadiene, 1,6-octadiene,1,7-octadiene, 1,9-decadiene, branched chain acyclic dienes, such as5-methyl-1,4-hexadiene; 3,7-dimethyl-1,6-octadiene;3,7-dimethyl-1,7-octadiene and mixed isomers of dihydromyricene anddihydroocinene, single ring alicyclic dienes, such as1,3-cyclopentadiene; 1,4-cyclohexadiene; 1,5-cyclooctadiene and1,5-cyclododecadiene, and multi-ring alicyclic fused and bridged ringdienes, such as tetrahydroindene, methyl tetrahydroindene,dicyclopentadiene, bicyclo-(2,2,1)-hepta-2,5-diene; alkenyl, alkylidene,cycloalkenyl and cycloalkylidene norbornenes, such as5-methylene-2-norbornene (MNB); 5-propenyl-2-norbornene,5-isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene,5-cyclohexylidene-2-norbornene, 5-vinyl-2-norbornene, and norbornadiene.Of the dienes typically used to prepare EPDMs, the particularlypreferred dienes are 1,4-hexadiene (HD), 5-ethylidene-2-norbornene(ENB), 5-vinylidene-2-norbornene (VNB), 5-methylene-2-norbornene (MNB),and dicyclopentadiene (DCPD). The especially preferred dienes are5-ethylidene-2-norbornene (ENB) and 1,4-hexadiene (HD).

One class of desirable elastomers that can be made in accordance withembodiments of the invention are elastomers of ethylene, a C₃-C₂₀α-olefin, especially propylene, and optionally one or more dienemonomers. Preferred α-olefins for use in this embodiment of the presentinvention are designated by the formula CH₂═CHR*, where R* is a linearor branched alkyl group of from 1 to 12 carbon atoms. Examples ofsuitable α-olefins include, but are not limited to, propylene,isobutylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and1-octene. A particularly preferred α-olefin is octene.

In yet another embodiment, selectively hydrogenated block copolymers canbe used as the toughening elastomer including block copolymers ofconjugated dienes and vinyl aromatic hydrocarbons which exhibitelastomeric properties and which have 1,2-microstructure contents priorto hydrogenation of from about 7% to about 100%. Such block copolymersmay be multiblock copolymers of varying structures containing variousratios of conjugated dienes to vinyl aromatic hydrocarbons includingthose containing up to about 60 percent by weight of vinyl aromatichydrocarbon. Thus, multiblock copolymers may be utilized which arelinear or radial, symmetric, or asymmetric and which have structuresrepresented by the formulae, A-B, A-B-A, A-B-A-B, B-A, B-A-B, B-A-B-A,(AB)_(0,1,2) . . . BA and the like wherein A is a polymer block of avinyl aromatic hydrocarbon or a conjugated diene/vinyl aromatichydrocarbon tapered copolymer block and B is a polymer block of aconjugated diene.

The block styrenic copolymers may be produced by any well known ionicblock polymerization or copolymerization procedures including the wellknown sequential addition of monomer techniques, incremental addition ofmonomer techniques or coupling techniques as illustrated in, forexample, U.S. Pat. Nos. 3,251,905, 3,390,207, 3,598,887, and 4,219,627,all of which are incorporated herein by reference. As is well known inthe block copolymer art, tapered copolymer blocks can be incorporated inthe multiblock copolymer by copolymerizing a mixture of conjugated dieneand vinyl aromatic hydrocarbon monomers utilizing the difference intheir copolymerization reactivity rates. Various patents describe thepreparation of multiblock copolymers containing tapered copolymer blocksincluding U.S. Pat. Nos. 3,251,905, 3,265,765, 3,639,521, and 4,208,356,the disclosures of which are incorporated herein by reference.

In certain embodiments, the polyolefin elastomer of the presentdisclosure has a density of from 0.850 g/cc to 0.900 g/cc. In certainembodiments, the polyolefin elastomer of the present disclosure has amelt index of from 0.1 g/10 min to 2000 g/10 min, according to ASTMD1238 or ISO 1133 at 190° C./2.16 kg (e.g., from 0.1 g/10 min to 500g/10 min, from 0.1 g/10 min to 100 g/10 min, from 0.1 g/10 min to 50g/10 min, from 0.1 g/10 min to 10 g/10 min, etc.).

Further parameters of the polyolefin elastomers (e.g., molecular weight,molecular weight distribution, melting temperature, etc.) will be knownby those of ordinary skill in the art based on the present disclosuresand can be determined by known methods in the polymer art.

Filler

The polyolefin blend compositions of the present disclosure canoptionally include one or more additives and/or fillers. Non-limitingexamples of additives and/or fillers include plasticizers, thermalstabilizers, light stabilizers (e.g., UV light stabilizers andabsorbers), antioxidants, slip agents, process aids, opticalbrighteners, antistats, lubricants, catalysts, rheology modifiers,biocides, corrosion inhibitors, dehydrators, organic solvents, colorants(e.g., pigments and dyes), surfactants, demolding additives, mineraloil, antiblocking agents, nucleating agents, flame retardants,reinforcing fillers (e.g., glass, fibers, anti-scratch additives, talc,calcium carbonate, mica, glass fibers, whisker, etc.), processing aids,and combinations thereof. In certain embodiments, the polyolefin blendcompositions comprise talc filler. In further embodiments, thepolyolefin blend compositions comprise from 1 wt % to 30 wt % of a talcfiller (e.g. from 1 wt % to 20 wt %, from 5 wt % to 15 wt %, etc.).

Composition

Without being bound by theory, it is believed that the olefin blockcopoylmer, as disclosed herein, acts as an effectivemodifier/compatibilizer between PE and PP phases in the TPO compositionsof the present disclosure to yield a fine rubber particle dispersionthat provides improved low temperature impact properties. The novelcompatibilized blends of PP and elastomers offer a wider range ofthermodynamically stable compositions with morphologies finer than thoseachievable with classical blends, resulting in unique combinations ofproperties, namely a combination of very high impact resistance attemperatures as low as −45° C., a melt flow rate allowing for easyprocessing in injection molding, a stiffness level suitable for easydemolding of complex injection molded parts, and improved temperatureresistance of the final part.

The polyolefin blend composition may be useful for preparing articlesusing known processes. For example, the compositions may be fabricatedinto parts, sheets or other article of manufacture, using any extrusion,calendering, blow molding, compression molding, injection molding, orthermoforming processes. The components of the composition may be fed tothe process either pre-mixed, or the components may be fed directly intothe process equipment, such as a converting extruder, such that thecomposition is formed therewithin. The compositions may be blended withanother polymer, prior to fabrication of an article. Such blending mayoccur by any of a variety of conventional techniques, one of which isdry blending of pellets of the compositions with pellets of anotherpolymer.

The polyolefin blend compositions may be compounded using, for example,a twin screw extruder, batch mixer, or single screw extruder.

Examples

Approximate conditions, properties, formulations etc., for thepreparation of the Examples are provided below.

Test Methods

Density is measured in accordance with ASTM D-792. The result isreported in grams (g) per cubic centimeter, or g/cc.

Melt index (MI) is measured in accordance with ASTM D-1238 (190° C.;2.16 kg). The result is reported in grams/10 minutes.

Melt flow rate (MFR) is measured in accordance with ASTM D-1238 (230°C.; 2.16 kg).

Izod Impact is measured according to ISO 180. Alternatively, Izod Impactis measured according to ASTM D256.

Tensile Properties, including tensile modulus, tensile yield strength,and tensile strain at break are measured in accordance with ISO 527.Alternatively, tensile properties are measured according to ASTM D638.

Flexural Modulus is measured in accordance with ASTM D790.Alternatively, Flexural Modulus is measured in accordance with ISO 178.

Molecular weight distribution (MWD) is measured using Gel PermeationChromatography (GPC). In particular, conventional GPC measurements areused to determine the weight-average (Mw) and number-average (Mn)molecular weight of the polymer and to determine the MWD (which iscalculated as Mw/Mn). Samples are analyzed with a high-temperature GPCinstrument. The method employs the well-known universal calibrationmethod, based on the concept of hydrodynamic volume, and the calibrationis performed using narrow polystyrene (PS) standards. The molecularweight determination is deduced by using narrow molecular weightdistribution polystyrene standards (from Polymer Laboratories) inconjunction with their elution volumes. The equivalent polyethylenemolecular weights are determined by using appropriate Mark-Houwinkcoefficients for polyethylene and polystyrene (as described by Williamsand Ward in Journal of Polymer Science, Polymer Letters, Vol. 6, 621(1968)) to derive the following equation:

Mpolyethylene=a*(Mpolystyrene)^(b).

In this equation, a=0.4316 and b=1.0 (as described in Williams and Ward,J. Polym. Sc., Polym. Let., 6, 621 (1968)). Polyethylene equivalentmolecular weight calculations were performed using VISCOTEK TriSECsoftware Version 3.0.

Gel permeation chromatographic (GPC) system consists of either a PolymerLaboratories Model PL-210 or a Polymer Laboratories Model PL-220instrument. The column and carousel compartments are operated at 140° C.Three Polymer Laboratories 10-micron Mixed-B columns are used. Thesolvent is 1,2,4 trichlorobenzene. The samples are prepared at aconcentration of 0.1 grams of polymer in 50 milliliters of solventcontaining 200 ppm of butylated hydroxytoluene (BHT). Samples areprepared by agitating lightly for 2 hours at 160° C. The injectionvolume used is 100 microliters and the flow rate is 1.0 ml/minute.

Calibration of the GPC column set is performed with 21 narrow molecularweight distribution polystyrene standards with molecular weights rangingfrom 580 to 8,400,000, arranged in 6 “cocktail” mixtures with at least adecade of separation between individual molecular weights. The standardsare purchased from Polymer Laboratories (Shropshire, UK). Thepolystyrene standards are prepared at 0.025 grams in 50 milliliters ofsolvent for molecular weights equal to or greater than 1,000,000, and0.05 grams in 50 milliliters of solvent for molecular weights less than1,000,000. The polystyrene standards are dissolved at 80° C. with gentleagitation for 30 minutes. The narrow standards mixtures are run firstand in order of decreasing highest molecular weight component tominimize degradation. The polystyrene standard peak molecular weightsare converted to polyethylene molecular weights using the followingequation (as described in Williams and Ward, J. Polym. Sci., Polym.Let., 6, 621 (1968)): M_(polypropylene)=0.645(M_(polystyrene)).

Differential Scanning Calorimetry (DSC) results are determined using aTAI model Q1000 DSC equipped with an RCS cooling accessory and anautosampler. A nitrogen purge gas flow of 50 ml/min is used. The sampleis pressed into a thin film and melted in the press at about 190° C. andthen air-cooled to room temperature (25° C.). 3-10 mg of material isthen cut into a 6 mm diameter disk, accurately weighed, placed in alight aluminum pan (ca 50 mg), and then crimped shut. The thermalbehavior of the sample is investigated with the following temperatureprofile. The sample is rapidly heated to 180° C. and held isothermal for3 minutes in order to remove any previous thermal history. The sample isthen cooled to −90° C. at 10° C./min cooling rate and held at −90° C.for 3 minutes. The sample is then heated to 180° C. at 10° C./minheating rate. The cooling (Tc) and second heating curves (Tm) arerecorded.

The DSC melting peak is measured as the maximum in heat flow rate (W/g)with respect to the linear baseline drawn between −30° C. and end ofmelting. The heat of fusion is measured as the area under the meltingcurve between −30° C. and the end of melting using a linear baseline.DSC can also be used to measure the soft segment melting temperature, asdiscussed in WO 2006/101966 A1, which is incorporated herein byreference in its entirety.

¹³C NMR spectroscopy is one of a number of techniques known in the artfor measuring comonomer incorporation into a polymer. An example of thistechnique is described for the determination of comonomer content forethylene/α-olefin copolymers in Randall (Journal of MacromolecularScience, Reviews in Macromolecular Chemistry and Physics, C29 (2 & 3),201-317 (1989)), which is incorporated by reference herein in itsentirety. The basic procedure for determining the comonomer content ofan ethylene/olefin interpolymer involves obtaining a ¹³C NMR spectrumunder conditions where the intensity of the peaks corresponding to thedifferent carbons in a sample is directly proportional to the totalnumber of contributing nuclei in the sample. Methods for ensuring thisproportionality are known in the art and involve allowance forsufficient time for relaxation after a pulse, the use ofgated-decoupling techniques, relaxation agents, and the like. Therelative intensity of a peak or group of peaks is obtained in practicefrom its computer-generated integral. After obtaining the spectrum andintegrating the peaks, those peaks associated with the comonomer areassigned. This assignment can be made by reference to known spectra orliterature, or by synthesis and analysis of model compounds, or by theuse of isotopically labeled comonomers. The mole % comonomer can bedetermined by the ratio of the integrals corresponding to the number ofmoles of comonomer to the integrals corresponding to the number of molesof all of the monomers in the interpolymer, as described in theaforementioned Randall reference.

The soft segment weight percentage and hard segment weight percentage ofan ethylene/olefin interpolymer of the present disclosure is determinedby DSC, and mole % comonomer in the soft segment of an ethylene/olefininterpolymer of the present disclosure is determined by ¹³C NMRspectroscopy and the methods described in WO 2006/101966 A1, which isincorporated herein by reference in its entirety.

¹³C NMR Analysis: The samples are prepared by adding approximately 2.7 gof a 50/50 mixture of tetrachloroethane-d²/orthodichlorobenzene to 0.2 gsample in a 10 mm NMR tube. The samples are dissolved and homogenized byheating the tube and its contents to 150° C. The data are collectedusing a JEOL Eclipse™ 400 MHz spectrometer, Bruker 400 MHz spectrometer,or a Varian Unity Plus™ 400 MHz spectrometer, corresponding to a ¹³Cresonance frequency of 100.5 MHz. The data is acquired using 256transients per data file with a 6 second pulse repetition delay. Toachieve minimum signal-to-noise for quantitative analysis, multiple datafiles are added together. The spectral width is 25,000 Hz with a minimumfile size of 32K data points. The samples are analyzed at 120° C. in a10 mm broad band probe. The comonomer incorporation is determined usingRandall's triad method (Randall, J. C.; JMS-Rev. Macromol. Chem. Phys.,C29, 201-317 (1989), which is incorporated by reference herein in itsentirety.

Standard CRYSTAF Method: Branching distributions are determined bycrystallization analysis fractionation (CRYSTAF) using a CRYSTAF 200unit commercially available from PolymerChar, Valencia, Spain. Thesamples are dissolved in 1,2,4 trichlorobenzene at 160° C. (0.66 mg/mL)for 1 hr and stabilized at 95° C. for 45 minutes. The samplingtemperatures range from 95 to 30° C. at a cooling rate of 0.2° C./min.An infrared detector is used to measure the polymer solutionconcentrations. The cumulative soluble concentration is measured as thepolymer crystallizes while the temperature is decreased. The analyticalderivative of the cumulative profile reflects the short chain branchingdistribution of the polymer. The CRYSTAF peak temperature and area areidentified by the peak analysis module included in the CRYSTAF Software(Version 2001.b, PolymerChar, Valencia, Spain). The CRYSTAF peak findingroutine identifies a peak temperature as a maximum in the dW/dT curveand the area between the largest positive inflections on either side ofthe identified peak in the derivative curve. To calculate the CRYSTAFcurve, the preferred processing parameters are with a temperature limitof 70° C. and with smoothing parameters above the temperature limit of0.1, and below the temperature limit of 0.3.

ATREF: Analytical temperature rising elution fractionation (ATREF)analysis is conducted according to the method described in U.S. Pat. No.4,798,081 and Wilde, L.; Ryle, T. R.; Knobeloch, D. C.; Peat, I. R.;Determination of Branching Distributions in Polyethylene and EthyleneCopolymers, J. Polym. Sci., 20, 441-455 (1982), which are incorporatedby reference herein in their entirety. The composition to be analyzed isdissolved in trichlorobenzene and allowed to crystallize in a columncontaining an inert support (stainless steel shot) by slowly reducingthe temperature to 20° C. at a cooling rate of 0.1° C./min. The columnis equipped with an infrared detector. An ATREF chromatogram curve isthen generated by eluting the crystallized polymer sample from thecolumn by slowly increasing the temperature of the eluting solvent(trichlorobenzene) from 20 to 120° C. at a rate of 1.5° C./min.

Blend Compositions

The following materials are principally used in the exemplarycompositions of the present application:

PP: A polypropylene copolymer having properties including a density of0.905 g/cc (ISO 1183) and a MFR of 25 grams/10 minutes (ISO 1133 at 230°C./2.16 kg) (available as PPC 9712 from Total Refining & Chemicals).

PE: A high density polyethylene resin having properties including adensity of 0.967 g/cc (ASTM D792) and a melt index of 8.3 g/10 minutes(ASTM D1238 at 190° C./2.16 kg) (available as DOW™ HDPE DMDA-8007 fromThe Dow Chemical Company).

OBC: An olefin block copolymer having properties including a density of0.8695 g/cc (ASTM D792) and a melt index of 0.5 g/10 minutes (ASTM D1238at 190° C./2.16 kg). (available as ENGAGE™ XLT 8677 available from TheDow Chemical Company).

POE: An ethylene-octene copolymer having properties including a densityof 0.870 g/cc (ASTM D792) and a melt index of 1.0 g/10 minutes (ASTMD1238 at 190° C./2.16 kg) (available as ENGAGE™ 8100 from The DowChemical Company).

Talc: Available as Imerys 700 talc.

All blends in Table 1 were compounded via twin screw extrusion (using aCoperion 18 mm extruder) and granulated into small pellets by a sidecutter granulator. The granulated compounds were then injection moldedas samples for testing.

In particular, Working Examples 1-4 and Comparative Examples A-E areprepared according to the following formulations and are analyzed withrespect to the following properties:

TABLE 1 Materials Ex. A Ex. B Ex. C Ex. 1 Ex. D Ex. 2 Ex. 3 Ex. E Ex. 4Formulation (parts by weight) PP 70 77.8 56 56 56 56 56 62.2 62.2 PE — —14 14 12.5 12.5 11 15.6 13.9 POE 20 22.2 20 — 21.5 18.5 17 22.2 20.6 OBC— — — 20 — 3 6 — 3.3 Talc 10 — 10 10 10 10 10 — — Properties @230° C.MFR 2.16 kg 11.6 13.6 9.1 7.6 9.0 7.6 — 10.8 10.6 (g/10 min) FlexuralMPa 1088 793 764 799 788 788 750 703 662 Modulus Tensile MPa 1050 767833 830 832 815 804 692 727 Modulus Yield MPa 16.4 16.3 16.2 15.3 15.815.3 14.9 15.6 15.3 Strength Tensile % 480 505 502 561 541 639 681 504623 Strain at Break Notched KJ/m² 53.7 50.5 56.0 56.7 57.0 56.0 55.651.9 52.1 Izod (RT) Notched KJ/m² 49.1 — 55.0 — — 58.9 58.6 — — Izod (0°C.) Notched Izod KJ/m² 32.6 29.3 40.2 50.9 — 48.9 51.6 56.9 61.1 (−20°C.) Notched Izod KJ/m² 9.6 11.1 8.3 44.9 9.4 20.7 26.2 49.1 54.8 (−30°C.) Notched Izod KJ/m² — 7.3 — — — — — 6.8 7.5 (−45° C.)

As seen from Table 1, it is clearly shown that, relative to thecomparative examples, Working Examples 1-4 with OBC ascompatibilizer/modifier surprisingly and unexpectedly showed significantimprovement in the low temperature toughness. The flow properties andother mechanical properties, including flex and tensile modulus, arealso very good with the addition of OBC.

1. A composition comprising: (A) from 30 wt % to 70 wt % of a propylenecomponent including at least one propylene based polymer having apropylene content of at least 70.0 wt %, based on the total weight ofthe propylene based polymer, and a melt flow rate from 1.0 g/10 min to100.0 g/10 min (ASTM D-1238 at 230° C., 2.16 kg); (B) from 1 wt % to 20wt % of an ethylene component including at least one ethylene basedpolymer having an ethylene content of at least 85.0 wt %, based on thetotal weight of the ethylene based polymer, and a melt index from 0.1g/10 min to 50.0 g/10 min (ASTM D-1238 at 190° C., 2.16 kg); (C) from 1wt % to 40 wt % of an olefin block copolymer; and at least one of (D)from 1 wt % to 40 wt % of a polyolefin elastomer and (E) from 1 wt % to30 wt % of a filler.
 2. The composition of claim 1, wherein the filleris talc.
 3. The composition as claimed in any one of claims 1 and 2,wherein the olefin block copolymer has a density from 0.850 g/cc to0.890 g/cc (ASTM D792) and a melt index from 0.1 g/10 min to 10.0 g/10min (ASTM D-1238 at 190° C., 2.16 kg).
 4. The composition as claimed inany one of claims 1 to 3, wherein the polyolefin elastomer has a densityfrom 0.850 g/cc g/cc to 0.890 g/cc (ASTM D792) and a melt index from 0.1g/10 min to 30.0 g/10 min (ASTM D-1238 at 190° C., 2.16 kg).
 5. Thecomposition as claimed in any one of claims 1 to 4, further comprising amelt flow rate of greater than 7.0 g/10 min at 230° C., 2.16 kg.
 6. Thecomposition as claimed in any one of claims 1 to 5, further comprising anotched impact of greater than 45.0 kJ/m² at −20° C.
 7. The compositionas claimed in any one of claims 1 to 6, further comprising a notchedimpact of greater than 20.0 kJ/m² at −30° C.
 8. The composition asclaimed in any one of claims 1 to 7, further comprising a notched impactof greater than 7.0 kJ/m² at −45° C.
 9. The composition as claimed inany one of claims 1 to 8, further comprising a flexural modulus ofgreater than 650 MPa.